1. Field of the Invention
The present invention relates to an air conditioning apparatus for a vehicle, which includes an air conditioning case having therein a first air passage and a second air passage partitioned from each other and introduces outside air and inside air into the first air passage and the second air passage, respectively.
2. Description of Related Art
Conventionally, an air conditioning apparatus for a vehicle is disclosed in JP-A-62-29411. In the conventional air conditioning apparatus, there are formed a first air passage for introducing outside air and a second air passage for introducing inside air, and first and second fans are disposed respectively in the first and second air passages and are driven by a motor. Further, a defroster air passage for blowing conditioned air toward an inner surface of a windshield of the vehicle is provided at a downstream air side of the first air passage, and a foot air passage for blowing conditioned air toward a foot side of a passenger in the passenger compartment of the vehicle is provided at a downstream air side of the second air passage. The defroster air passage and the foot air passage are respectively opened and closed by a defroster switching door and a foot switching door. Further, the first air passage and the second air passage communicate with each other at a downstream air side thereof. The foot switching door is formed so that the first air passage and the second air passage are entirely partitioned from each other by the foot switching door when the foot switching door opens the foot air passage.
The inventors of the present invention have studied the conventional air conditioning apparatus. As a result, in a double laminar mode, when an operation mode is switched from a foot air mode where a ratio of an air volume flowing in the first air passage and an air volume flowing in the second air passage is approximately 1/9 or 2/8 to a foot/defroster air mode where the ratio of air volumes is approximately 5/5, or the operation mode is switched from the foot/defroster air mode to the foot air mode, an opening degree of the defroster switching door is greatly changed (rotated) so that the ratio of air volumes is changed. That is, because the first fan and the second fan are driven by the same motor, the ratio of the air volumes is not adjusted by controlling rotational speeds of the first and second fans. Thus, a rotational opening degree of the defroster switching door becomes large when the defroster switching door is driven by a link mechanism, or a rotational amount of a servo motor becomes large when the defroster switching door is driven by the servo motor, for example.